Unfortunately you can't send bubble or screen effects with the iPhone 4s or any previous models. The ability to send balloons, confetti, lasers and so on through the Messages app requires iOS 10.0 or later. The iPhone 4s does not support iOS 10.
iPhone 4s owners will also not be able to see any bubble or message effects sent to them. Effects sent to users with unsupported devices will see a blank (sent with _____) message instead.